Such a procedure and such a control unit are already known from DE 100 63 750 A1. In this script one of several cylinders is used for pumping air out of the suction system into the exhaust gas system while fuel supply is disabled. The amount of the pumped air is controlled by interventions in a variable valve control of this cylinder. The turbo charger can be waived at the known subject and is therefore not significant for the pumping of air. Variable valve controls are furthermore known for example from the pocket book on motor vehicle technology, 25th edition, ISBN 3-528-23873-3, Robert Bosch GmbH, 2003, p. 474 and 475.
The heating of a catalyst by producing a reactive exhaust gas fuel/air mixture in the exhaust gas system is also already known from the publication of DE 100 63 750 A1 as injecting secondary air in a rich exhaust gas atmosphere. The secondary air is usually injected behind the outlet valves of the combustion engine and reacts there exothermically with a rich exhaust gas atmosphere, which results from combustions of combustion chamber fillings of the combustion engine. For injecting secondary air usually a separate secondary air pump is used, which is electronically driven.
The subject known from DE 100 63 750 A1 temporarily uses a cylinder of the combustion engine as a secondary air pump, so that a separate secondary air pump that is driven electrically or mechanically can be waived. But then the concerned cylinder is not available for a torque generation, which causes an increased uneven running.
It is for example known to produce a maximum heat quantity in the exhaust gas during an after-start phase of the combustion engine, without changing the power that has been raised in idle mode and the idle toque of ca. 1.200 min-1 that has been increased in the after-start phase. This is achieved at a combustion engine with a direct fuel injection thereby that a first percentage of the fuel amount is injected into the suction stroke and a second percentage of the fuel amount into the compression stroke. This results in a layered fuel apportionment in the combustion chamber with a zone of comparably rich and therefore well ignitable fuel/air mixture around the ignition plug that results from the injection of the second percentage. This operation of the combustion engine is also called homogeneous split mode, whereby split refers to the apportionment of the injection.
A charging concept with an exhaust gas turbo charger is known from DE 100 62 377 A1, whereby its shaft is driven by an electromotor. This drive shall reduce the so-called ‘turbo lag’ at operating point changes. The turbo lag originates as it is well known thereby that the turbine has to be initially accelerated at a sudden torque demand from an operating point with a low exhaust gas mass flow, in order to produce the required boost pressure on the compressor side. The supporting electronic drive reduces the resulting delay.
This charging concept, which has basically nothing to do with a catalyst heating procedure, is used in DE 100 62 377 A1, in order to replace the separate secondary air pump. Thereby the turbo charger is electronically driven when the catalyst has to be heated. Thereby it already produces a certain boost pressure even in operating points with low exhaust gas enthalpy, which is sufficient to let air flow out of the suction system over a pipe connection past the combustion chambers of the combustion engine into the exhaust gas system. Thereby a separate secondary air pump can be waived at turbo chargers that are supported by an electrical drive. But the secondary air injection requires even at these charging concepts an electric drive.